I recently bought a new laptop, and I am trying to dual boot my system with windows 8.1 and ubuntu. My installer doesn't recognize the windows 8 partition on my hard drive, so it doesn't give me the option to install alongside windows. I can see a large partition that is supposed to be my windows partition in the installer, but it doesn't recognize that it is windows. I have turned off secure boot and fast start-up, but there is no difference. I am thinking about manually partitioning my hard drive in the Ubuntu installer. I have two questions:

First, I am planning on partitioning it with 16 GB swap, which is the amount of ram on my laptop, and about 20 GB for a '/' root logical partition. Is this a good setup for the installer?

My second question is about the grub menu. If I do the manual install, will grub recognize my windows partition even though the ubuntu installer doesn't? Meaning when I see the grub menu, will it just list /dev/sd# or will it say Windows like before, or maybe not even show it at all?

Are you booting install in UEFI mode, not in BIOS mode? How you boot installer is how it installs. Also only use Windows to shrink the Windows NTFS partition and reboot before install so it can run chkdsk and make repairs. Do not create partitions with Windows. Best to have good backups of Windows, efi partition and make a repair flash drive for Windows. help.ubuntu.com/community/UEFI AND: askubuntu.com/questions/221835/…
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oldfredApr 19 '14 at 21:39

Suspend-to-disk (aka hibernate) operations require at least as much swap space as you have RAM, so if you intend to use that function, you need more swap space. That said, suspend-to-disk is often broken, and some people don't use it even when it works fine, so this may not be a factor.
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Rod SmithApr 19 '14 at 22:34

The failure to recognize Windows in the installer is a bug in the installer, not a bug in GRUB. In theory, GRUB should detect Windows just fine once you install via the "Something Else" option in the installer. That said, I can't make any promises; GRUB can be pretty finicky about starting Windows on EFI systems, so you might run into some unrelated problem.

Personally, I'd shrink the Windows partition by much more than you're suggesting and set aside more space for a shared-data partition. This will minimize the risk of accessing the Windows partition from Linux (since you won't need to do it), while still enabling you to share data between the two OSes.

(Actually, that's a lie; I wouldn't use Windows more than two or three times a year, so I'd give most of my space to Linux. That's another discussion, though....)